1. Field of the Invention
This invention relates to a method and system for charging a container with pressurized gaseous fuel.
2. Description of Prior Art
Extending the driving range of natural gas vehicles is important for wide-spread acceptance of natural gas vehicles among consumers as a favorable environmental alternative to gasoline and diesel vehicles.
One obstacle to obtaining the maximum usable capacity of a natural gas vehicle (NGV) cylinder is the increased internal cylinder pressure necessary to completely charge a NGV cylinder in relatively warm ambient temperatures. Because there is a direct relationship between the internal pressure and the internal temperature in a constant volume cylinder for a given mass of gas, the higher the temperature of the gas, the greater the supply pressure necessary to charge the cylinder with a given mass of gas. A NGV cylinder often reaches its maximum internal design pressure before being fully charged, particularly in such relatively warm temperature conditions.
U.S. Pat. Nos. 5,121,609, 5,228,295, and 5,231,838 generally teach fueling systems for delivering liquid natural gas and compressed natural gas to natural gas vehicles.
U.S. Pat. No. 5,315,831 teaches a fueling system that delivers liquid natural gas and compressed natural gas to natural gas vehicles, the compressed gas being generated by heating liquid natural gas.
U.S. Pat. No. 5,107,906 teaches a fueling system for fast-filling a natural gas vehicle cylinder, also by heating a supply of liquid natural gas.
None of the above-mentioned patents teach a system or method for ensuring a complete charge of a natural gas cylinder in relatively warm ambient temperatures. Thus, it is apparent that there is a need for a natural gas fueling station that can completely fast-fill a natural gas cylinder, regardless of the ambient temperature.